1. Field of the Invention
The present invention relates to an image formation apparatus of storing image data in an optical image memory by beam light, reading the stored image and printing it out.
2. Description of the Prior Art
U.S. Pat. No. 3,796,999 discloses a display in which laser light selectively illuminates a liquid crystal cell and liquid crystal makes an image visible. In this display, heat of the laser light is utilized to partially vary a phase of the liquid crystal; the image is formed in accordance with an irradiation pattern of the laser light. The liquid crystal employed may be a smectic liquid crystal, for example.
Also, Japanese Unexamined Patent Publication No. 20773/1989 discloses a device using the above-mentioned thermal writing liquid crystal cells for forming an image irradiating a light transmitted or reflected by the liquid crystal to a photosensitive material, a latent image is formed on the photosensitive material; the latent image is used to make an image. With three liquid crystal cells, for example, images of primary colors, R(red), G(green) and B(blue), are written in the cells, and a full color image is composed of the three images.
However, in such a conventional image formation device, if it is necessary to partially change an image written in liquid crystal cells, partial erasing and writing of the image on one of the liquid crystal cells is impossible; therefore, it is necessary to erase all the image and then write a novel image. Then, there arises the problem that it requires long time to perform the writing.